Postoperative infection following orthognatic surgery is rare. When postoperative infections occur, the initial treatment consists of incision and drainage of the affected area, culturing to identify bacterial stains and verify antibiotic sensitivity, and the institution of the appropriate antibiotic regimen. Some plates and screws may eventually require removal, the initial therapy should be attempted to retain the plates and screws until adequete healing has taken place. In orthoganthic surgery, intra-operative complications as a lesion of inferior alveolar nerve, fracture of osteomised segments, incomplete sectioning, malposition of segments, haemorrhage may occur. The surgeon should be familiar with possible complications to be caused and how to manage them. Prevention of postoperative infection following the orthognathic surgery consists of minimal periosteal reflection, aseptic management of operation field, proper surgical technique, rigid fixation, prophylactic antibiotics.